I am new to the site and could not find an answer to this. I posted this question on the Pistol Forum and it was suggested I post it here.

I recently bought a Bushmaster Carbon 15 Type 97S Pistol with a 7.25" barrel. As I understand it, the advantage of the AR-15 .223 for personal defense is the fragmentation that occurs. As I further understand it, fragmentation begins at around 2700 ft/sec, reaches 75% at 2900, and is 100% by 3300; depending on the bullet.

I did not realize the relation between muzzle velocity and barrel length. It appears that with this short of a barrel length sufficient velocities cannot be obtained.

Is there any ammunition that can properly fragment with this gun? Is there any way to extend the barrel length?

Originally Posted By Neo1:For the pistol for self defense would people suggest the FRANGIBLE round above or a 40 grain Nosler?

Gosh no! Please take some time and read those articles by Dr Fackler in the links posted at the top of this forum.

You need a minium of 12" of penetration and NONE Of the light varmint type rounds (nor frangibles) will have anything near enough penetration.

You're best bet is to try some 75gr OTMs (Like Black Hills) at home distances (15'-20') it may work (you should get the penetration at least - you can test for fragmentation with some jugs filled with water).

I'd also suggest learning American sign language - cause if you touch those .223 rounds off from a 7" barrel inside a house your ears will take a hit.

Originally Posted By Troy:A 5.56 AR pistol is an exceedingly poor home defense weapon, regardless of ammo.

-Troy

Troy is it even possible to get consitant reliable fragmentation form say a 75gr round out of a barrel that short? Jeff Hoffman made some comments here a good while back that made it sound like they would not reliable fragment out of barrels under 10.5 if even that barrel length.

I just received an email from Bushmaster that a 11.5" barrel can be installed. I think a 40 grain bullet would provide sufficient velocity as Hornady says that their 40 grain bullet has a velocity of 2650 with an 8 1/2" barrel.

The 75 gr bullet was a BT HP. The others were plastic tipped (Nosler style) HP. On this preliminary data, it appears the BT HP may fragment at lower speeds that the Nosler style. With the BT HP 72% fragmentation was achieved at only 2615 fps. The Nosler style required 2910 fps for 75% fragmentation. Have studies been done comparing the fragmentation % of the BT HP with the Nosler Style bullet at various velocities?

If we can extrapolate from these two data sets the 40 gr bullet should fragmentation in excess of 75%. A higher weight BT HP should also achieve sufficient fragmentation

Although the data is limited, I believe the 11.5" barrel would turn the pistol into a very effective weapon. I would prefer a 14.5" barrel.

Originally Posted By CRC:55 FMJ is the most reliable round out there but heavy hollowpoints over 67 grains are better

Every study that I have seen shows that the FMJ does not fragment. The fragmentation is so important to the .223.

From the information above:

For the 11.5" barrel:

Weight Velocity55 2872 62 2738

We lose 19.14 fps with each additional GR ((2872-2738)/(62-55).This would give a 69 GR bullet a velocity of 2604. This is very close to the 72% fragmentation of the TAP 75 GR at 2615 fps. In addition, the Federal GM223M 69 GR BT JHP has an energy of 1379 as opposed to 1296 for the TAP 75 GR BT JHP. This should give the Federal 69 GR BT JHP even more velocity and make it an excellent bullet for the pistol with a 11.5" barrel.

I know this involves extrapolation to a different bullet but the reasoning seems sound. What do others think?

Interesting that this information gives the 40 GR bullet an excellent 1 shot stopping % of 99%. I do not see the 69 GR JHP-BT on Winchester's site but this adds data to support that this is an excellent bullet. I am surprised how well the FMJ performs.

Interesting that this information gives the 40 GR bullet an excellent 1 shot stopping % of 99%. I do not see the 69 GR JHP-BT on Winchester's site but this adds data to support that this is an excellent bullet. I am surprised how well the FMJ performs.

Thoughts?

It may be great for one shot stops on little animals, but it's not a good round to bet yer life on period end of story.

Thanks for the advice. I have read the pinned topics and am working my way through the suggested thread. I called Bushmaster today and will be sending the pistol in tomorrow for the 11.5" barrel replacement. One of the problems I am having is that there is little data on this gun with the 11.5" barrel.

I spoke with an ex swat team member for the Highway Patrol where I purchased the gun and he suggested the 40 gr bullet. The one site I listed also suggests it. It seems everyone here thinks it would be a poor choice.

Would the Federal 69 gr JHP-BT be a good choice for the Bushmaster pistol with the 11.5" barrel?

Originally Posted By Neo1:Thanks for the advice. I have read the pinned topics and am working my way through the suggested thread. I called Bushmaster today and will be sending the pistol in tomorrow for the 11.5" barrel replacement. One of the problems I am having is that there is little data on this gun with the 11.5" barrel.

I spoke with an ex swat team member for the Highway Patrol where I purchased the gun and he suggested the 40 gr bullet. The one site I listed also suggests it. It seems everyone here thinks it would be a poor choice.

Would the Federal 69 gr JHP-BT be a good choice for the Bushmaster pistol with the 11.5" barrel?

I appreciate the help!

Depending on the barrel twist, yes. I run a 1/9 twist 11.5 in barrel on my SBR my personal choice right now for defensive ammo is the black hills 75gr BTHP. I still hven't been able to get my hands on any hornady 75gr TAP ammo so I don't know how the gun likes it.

As Forest stated the problem with the light bullets is that they are designed for animals, and small ones at that. They do not penetrate enough at least based on the 12in minimum set forth by the FBI in thier standards. The problem with a round that doesn't penetrate enough is that it's less likely to reach the places it needs to to do the damage to stop a threat.

The Bushmaster has a 1/9 barrel twist. I understand the the penetration issue. I am trying to balance this with having the bullet moving fast enough at less than 10 yrds and the 11.5" barrel to fragment as much as possible.

The Federal 69 gr JHP-BT is a little lighter than the 75 gr TAP and is a little "hotter" with more energy.

Originally Posted By Neo1:The Bushmaster has a 1/9 barrel twist. I understand the the penetration issue. I am trying to balance this with having the bullet moving fast enough at less than 10 yrds and the 11.5" barrel to fragment as much as possible.

The Federal 69 gr JHP-BT is a little lighter than the 75 gr TAP and is a little "hotter" with more energy.

Thanks again!

Its not hotter if you get the 5.56 75 grain ammo. 69 grain ammo has a later yaw and fragments deeper than 75 grain ammo and has a higher fragmentation floor. I would not even consider it in any way a competition to the 75 grain TAP round for your use.

Originally Posted By Neo1:I understand the the penetration issue. I am trying to balance this with having the bullet moving fast enough at less than 10 yrds and the 11.5" barrel to fragment as much as possible.

The Federal 69 gr JHP-BT is a little lighter than the 75 gr TAP and is a little "hotter" with more energy.

Thanks again!

Its not hotter if you get the 5.56 75 grain ammo. 69 grain ammo has a later yaw and fragments deeper than 75 grain ammo and has a higher fragmentation floor. I would not even consider it in any way a competition to the 75 grain TAP round for your use.

Please forgive my ignorance as I am new to the AR-15 and I read conflicting reports both here and elsewhere. As I understand it, the lighter grain yaws and fragments earlier with less deep penetration. If one compares the Federal vs. the Hornady on their sites, the Federal has more energy. I am not LE so I do not have access to these bullets. Is the 5.56 (NATO) round available in a JHP? Where?

Originally Posted By Neo1:I understand the the penetration issue. I am trying to balance this with having the bullet moving fast enough at less than 10 yrds and the 11.5" barrel to fragment as much as possible.

The Federal 69 gr JHP-BT is a little lighter than the 75 gr TAP and is a little "hotter" with more energy.

Thanks again!

Its not hotter if you get the 5.56 75 grain ammo. 69 grain ammo has a later yaw and fragments deeper than 75 grain ammo and has a higher fragmentation floor. I would not even consider it in any way a competition to the 75 grain TAP round for your use.

Please forgive my ignorance as I am new to the AR-15 and I read conflicting reports both here and elsewhere. As I understand it, the lighter grain yaws and fragments earlier with less deep penetration. If one compares the Federal vs. the Hornady on their sites, the Federal has more energy. I am not LE so I do not have access to these bullets. Is the 5.56 (NATO) round available in a JHP? Where?

Thanks once again.

Every round is different. Sierra bullets yaw later than the Hornady counterparts 77/75 and 69/68. Never look at energy figures to determin terminal effectiveness they have no corrolation or causation to one another. JHP rounds underpenetrate as do all ballistic tips in .223

I suggest doing searches in tacticalforums.com in the terminal effects forum but DO NOT POST till you do some searches as you will find data on most every type of ammo you could think of.

I give up. I have spent hours each day reading this site and across the internet. I have the Bushmaster pistol and the 11.5' barrel is being installed. I have not seen any tests with this barrel. It seems that most here would suggest the 75gr TAP or 75gr Black Hills.

At this point I would like to hear the best guess from the experts here for what ammo would be most effective for personal defense within a home with a max of 10 yards. Perhaps the most important features are reliability, fragmentation, and penetration.

I already told you where to go to get SPECIFIC DATA thought bare gelatin, windshields, barriers etc on 11.5" barrels tested with all the OTM loads and you give up? You have already been told the 75 grain loading is the best factory loading you can find for use as everything but a barrier round. You were told where to confirm this from testing done by "the experts" what else do you want? Did you just get pissy because the less expensive 69 grain loads do not perform as well?

I went to the site you suggested and spent a fair amount of time searching on short barrels and 11.5 barrels. I think I found 4 threads on the .223 and 11.5" barrels. There was some interesting discussion but I did not find specific data with gelatin and 11.5" barrels. Perhaps I used the wrong keywords for my searches. I will search again. I welcome any specific keywords or the URL for the thread(s) that have the specific tests.

I am not set on any particular load for the pistol yet. I have decided the 75 gr TAP is best for my 16" rifle and probably for the pistol as well. From the testing above the Hornady TAP 75 gr has a muzzle velocity of 2616 and fragmentation of 72% with a 16" barrel. According to my best estimates the TAP 75 gr will have a muzzle velocity of 2427 with an 11.5" barrel. I wonder what the fragmentation % is at this velocity?

I sincerely appreciate all the help you and others have given me here and would welcome any other thoughts.

1. Adequate penetration. Experts worldwide agree that ideal bullet penetration depth should be 12"-16", with the 12" minimum being extremely important. This is to ensure that the bullets can reach the vital organs regardless of the angle of the shot and/or having to penetrate an arm to get to the torso. If a load doesn't meet minimum specs here, forget it.

2a. For rifles, you look for bullet fragmentation, as a fragmenting bullet makes the best use of the power available in a rifle cartridge when it comes to damaging tissue. Testing is required to find which bullets cause the largest amount of tissue damage, and whether the damage is located in the desired location along the wound path.

2b. For handguns, you look for reliable bullet expansion, since handgun bullets are large and slow, and don't have the fragmentation abilities of a rifle bullet. You want a bullet that will expand quickly and reliably, even after passing through various intermediate barriers. You also want to ensure that the bullet doesn't shed its jacket, which means you want a bonded bullet.

3. After the above has been satisfied, you can look at things like muzzle flash/blast, recoil, and how reliably the round works in your rifle or handgun. Price would also be looked at here.

What you posted makes a lot of sense to me. For me, the single most important factor is reliability. If I am faced with an armed intruder and my weapon jams or does not fire for some other reason then I am in a very bad situation. Although legally the AR pistols are classified as pistols they perform like AR rifles with short barrels. Despite hours and hours of searching on the net, these seem to be ignored in terms of actual documented testing with data.

To me the effectiveness of the .223 comes from a combination of penetration and % fragmentation. The Hornady TAP 75 gr seems ideal for my 16" rifle as it seems to have a fragmentation % of 72% at 2616 fps. By my best estimates an 11.5" barrel decreases velocity to 87 % of the manufacturers advertised velocity with a 24" barrel. I do not know how much the 75 gr TAP would fragment at 2427 fps.

I just came across Winchester's SBST223 50 gr "Nosler style" round. Advertized velocity (24" barrel) is 3410 fps. Calculated velocity for an 11.5" barrel is 2967. This should provide at least 75% fragmentation.

NO 5.56 "ballistic tip" bullet will give enough penetration. That means no Hornady VMax or AMax, no Nosler Ballistic Tip, no Sierra BlitzKing, and no Combined Technologies bullet. All of these bullets were designed for VARMINT hunting, against creatures 60 pounds and under. None are suitable for combat/defense from ANY 5.56 weapon.

Originally Posted By Troy:NO 5.56 "ballistic tip" bullet will give enough penetration. That means no Hornady VMax or AMax, no Nosler Ballistic Tip, no Sierra BlitzKing, and no Combined Technologies bullet. All of these bullets were designed for VARMINT hunting, against creatures 60 pounds and under. None are suitable for combat/defense from ANY 5.56 weapon.

-Troy

What about the new Swift 75gr Scirocco II bullet it's ment for use on deer and similar sized animals but it is a polymer tiped bullet. It's a bonded bullet as well. Have you or are you aware of any testing of this particular bullet? I don't know of anyone that loads it in a factory load yet but I'm looking at it for a hog/deer round for the AR15. I haven't been able to find any testing data on it as far as penetration tests/gel tests or anything like that. If yer aware of anything I'd love to see it.

Originally Posted By Troy:NO 5.56 "ballistic tip" bullet will give enough penetration. That means no Hornady VMax or AMax, no Nosler Ballistic Tip, no Sierra BlitzKing, and no Combined Technologies bullet. All of these bullets were designed for VARMINT hunting, against creatures 60 pounds and under. None are suitable for combat/defense from ANY 5.56 weapon.

-Troy

Hi Troy

The TAP 55 & 60 gr bullets are "ballistic tip", are they not? These are supposed to be for combat/defense.

In a sense, humans are like large varmits as we have a thin "hide" compared to large wildlife.

Originally Posted By JJREA:Hey photoman, I though outdoor marksman has TAP. I'll go look.

NIS sorry.

They probably do, but I can't use it for hunting(it's not an "expanding" ammo DNR already told me they don't consider "fragmenting ammo" as expanding) I just use BH blue box 75gr for the HS/SD ammo. The other thing being that if the Swit bullet turns out to be a good round for a SD/HD round then that would simplify things for me a good bit. Bonded bullets are suposed to be better for barrier penetration as well(like say auto glass).

Originally Posted By Troy:NO 5.56 "ballistic tip" bullet will give enough penetration. That means no Hornady VMax or AMax, no Nosler Ballistic Tip, no Sierra BlitzKing, and no Combined Technologies bullet. All of these bullets were designed for VARMINT hunting, against creatures 60 pounds and under. None are suitable for combat/defense from ANY 5.56 weapon.

-Troy

Hi Troy

The TAP 55 & 60 gr bullets are "ballistic tip", are they not? These are supposed to be for combat/defense.

In a sense, humans are like large varmits as we have a thin "hide" compared to large wildlife.

Just because they are marketed as such, don't mean they are. Troy and other experts have found any of the ballistic tips to fragment violently but not penetrate enough. (12" minimum). Which includes the 3rd one on your list, the 50 grain nosler.

This is getting old. Your best bet are any of the 75 grain loadings. There are more than just TAP. The second best would be the 77 loadings. There are more than one. Your next step is to find out which one you want to buy and from whom. If this is too much for you to figure out, you need a shotgun with my suggestion is #4 buck. (everyone don't flame me it was just a joke, although I do like it).

Photoman, I'm in the same boat with you obviously. It's a new bullet and I don't know if tests have been done on it, but it seems like it would be the ticket for us to choose to hunt with an AR. I may be starting to handload soon!!!!

Originally Posted By Troy:NO 5.56 "ballistic tip" bullet will give enough penetration. That means no Hornady VMax or AMax, no Nosler Ballistic Tip, no Sierra BlitzKing, and no Combined Technologies bullet. All of these bullets were designed for VARMINT hunting, against creatures 60 pounds and under. None are suitable for combat/defense from ANY 5.56 weapon.

-Troy

Hi Troy

The TAP 55 & 60 gr bullets are "ballistic tip", are they not? These are supposed to be for combat/defense.

In a sense, humans are like large varmits as we have a thin "hide" compared to large wildlife.

Just because they are marketed as such, don't mean they are. Troy and other experts have found any of the ballistic tips to fragment violently but not penetrate enough. (12" minimum). Which includes the 3rd one on your list, the 50 grain nosler.

This is getting old. Your best bet are any of the 75 grain loadings. There are more than just TAP. The second best would be the 77 loadings. There are more than one. Your next step is to find out which one you want to buy and from whom. If this is too much for you to figure out, you need a shotgun with my suggestion is #4 buck. (everyone don't flame me it was just a joke, although I do like it).

Photoman, I'm in the same boat with you obviously. It's a new bullet and I don't know if tests have been done on it, but it seems like it would be the ticket for us to choose to hunt with an AR. I may be starting to handload soon!!!!

However, if it's bonded, I don't know if it'll fragment at all.

Fragment it won't it's designed to act as a SP/expanding HP bullet would, the polymer tip acts as a way to protect the bullet tip from damage durring feeding and it also has a secondary effect of increasing the BC of the bullet. According to swift though it was designed around a 1/8 twist(which is why I was asking about the Hbar barrel you got on that rifle you had out with ya. I was thinking of getting two barrels and having one cut down to 11.5 for the SBR and keeping one 16in for the "DM" rifle.

I;d still probably stick with the 75gr BTHP for HD/SD but if the 75gr from swift is any good in penetration test for auto glass or the like, it would be handy to keep somem on hand for that reason too(hey ya never know when ya might need to use it for that right)

The TAP 55 & 60 gr bullets are "ballistic tip", are they not? These are supposed to be for combat/defense.

In a sense, humans are like large varmits as we have a thin "hide" compared to large wildlife.

The 55gr and 60gr TAP loads use VMax bullets, which as I said, were designed for small varmints and underpenetrate (compared to human combat requirements; they do just fine for the varmints they were designed for). Putting these loads in TAP boxes and marketing them as police loads does not change their performance.

The only reason these loads exist is because many police departments choose their duty loads based not on the effectiveness of the load stopping a criminal, but on the effectiveness of the load reducing their imagined legal liabilties. A great many departments do little or no testing, or use a load simply because someone high up in the department "decided" (without any actual research or testing) that it was a good load.

The Swift Scirocco bullet is brand new and has not been tested, but it was designed with a totally different goal in mind than the other ballistic tip designs in this caliber, so it could well be the exception. Until it can be tested in detail (a very time consuming and extremely expensive task), we just don't know for sure.

Originally Posted By photoman:Troy I got a coup[le questions for ya, but I'll IM them to ya as they are OT, probably later today or tomarrow.

It's better if you post them (make another topic if need be), that way everyone will be able to see the answer (and I may or may not be the one providing it; I don't know everything).

-Troy

Well the questions revolve around Perma-Gel ballistic gel. sold at cabelas. Particularly if you or anyone else you know might have used this stuff and have any opinions on it.

In the description it says it mimicks large animal body/ muscle tissue. My question was if this stuff will calabrate the same as 10% ballistic gel(using the BB like yer suposed to) if it would be a good thing to use for some at home testing. I'm looking at gettign some of the SWIFT bullets loaded up some time in the next couple months and I was looking to test them at various velocities and distances from both a 16in and 11.5 in barrel. While I think it would be fine using this stuff to see how it would do on deer size game and hogs I was wondering how close it would give me for results on "human" targets as well.

Originally Posted By photoman:Well the questions revolve around Perma-Gel ballistic gel. sold at cabelas. Particularly if you or anyone else you know might have used this stuff and have any opinions on it.

In the description it says it mimicks large animal body/ muscle tissue. My question was if this stuff will calabrate the same as 10% ballistic gel(using the BB like yer suposed to) if it would be a good thing to use for some at home testing. I'm looking at gettign some of the SWIFT bullets loaded up some time in the next couple months and I was looking to test them at various velocities and distances from both a 16in and 11.5 in barrel. While I think it would be fine using this stuff to see how it would do on deer size game and hogs I was wondering how close it would give me for results on "human" targets as well.

Photoman - do a search. There was a thread or two on this stuff in December or Mid January IIRC. It included Dr Roberts making a couple of comments. IIRC he indicated the Perma-Gel did not accurately reflect the temporary cavity, and that it worked best for the bare-gel test of handgun bullets.

Originally Posted By photoman:Well the questions revolve around Perma-Gel ballistic gel. sold at cabelas. Particularly if you or anyone else you know might have used this stuff and have any opinions on it.

In the description it says it mimicks large animal body/ muscle tissue. My question was if this stuff will calabrate the same as 10% ballistic gel(using the BB like yer suposed to) if it would be a good thing to use for some at home testing. I'm looking at gettign some of the SWIFT bullets loaded up some time in the next couple months and I was looking to test them at various velocities and distances from both a 16in and 11.5 in barrel. While I think it would be fine using this stuff to see how it would do on deer size game and hogs I was wondering how close it would give me for results on "human" targets as well.

Photoman - do a search. There was a thread or two on this stuff in December or Mid January IIRC. It included Dr Roberts making a couple of comments. IIRC he indicated the Perma-Gel did not accurately reflect the temporary cavity, and that it worked best for the bare-gel test of handgun bullets.

Thanks for the info Forest, I kinda figured that might be the case(the comments from Dr. Roberts) I'll do a search and see what i come up with.

Originally Posted By photoman:Well the questions revolve around Perma-Gel ballistic gel. sold at cabelas. Particularly if you or anyone else you know might have used this stuff and have any opinions on it.

In the description it says it mimicks large animal body/ muscle tissue. My question was if this stuff will calabrate the same as 10% ballistic gel(using the BB like yer suposed to) if it would be a good thing to use for some at home testing. I'm looking at gettign some of the SWIFT bullets loaded up some time in the next couple months and I was looking to test them at various velocities and distances from both a 16in and 11.5 in barrel. While I think it would be fine using this stuff to see how it would do on deer size game and hogs I was wondering how close it would give me for results on "human" targets as well.

Photoman - do a search. There was a thread or two on this stuff in December or Mid January IIRC. It included Dr Roberts making a couple of comments. IIRC he indicated the Perma-Gel did not accurately reflect the temporary cavity, and that it worked best for the bare-gel test of handgun bullets.

Thanks for the info Forest, I kinda figured that might be the case(the comments from Dr. Roberts) I'll do a search and see what i come up with.

Hey photoman, do you have any experience with the 64 grainers? I think they do fragment some and would be totally legal, obviously. But they seem to have terrible ballistics downrange in comparison to match loads of course but if we just study how they drop, it might not be a bad choice. When you going to bring your sticks over to the 600 where the real men shoot? I'm just kidding, the farthest I've shot is 300 and that was with my garand. My goal is this year, all the way out to 600 with the carbine!!!!!!!

Originally Posted By photoman:Well the questions revolve around Perma-Gel ballistic gel. sold at cabelas. Particularly if you or anyone else you know might have used this stuff and have any opinions on it.

In the description it says it mimicks large animal body/ muscle tissue. My question was if this stuff will calabrate the same as 10% ballistic gel(using the BB like yer suposed to) if it would be a good thing to use for some at home testing. I'm looking at gettign some of the SWIFT bullets loaded up some time in the next couple months and I was looking to test them at various velocities and distances from both a 16in and 11.5 in barrel. While I think it would be fine using this stuff to see how it would do on deer size game and hogs I was wondering how close it would give me for results on "human" targets as well.

Photoman - do a search. There was a thread or two on this stuff in December or Mid January IIRC. It included Dr Roberts making a couple of comments. IIRC he indicated the Perma-Gel did not accurately reflect the temporary cavity, and that it worked best for the bare-gel test of handgun bullets.

Thanks for the info Forest, I kinda figured that might be the case(the comments from Dr. Roberts) I'll do a search and see what i come up with.

Hey photoman, do you have any experience with the 64 grainers? I think they do fragment some and would be totally legal, obviously. But they seem to have terrible ballistics downrange in comparison to match loads of course but if we just study how they drop, it might not be a bad choice. When you going to bring your sticks over to the 600 where the real men shoot? I'm just kidding, the farthest I've shot is 300 and that was with my garand. My goal is this year, all the way out to 600 with the carbine!!!!!!!

I've had them on the 600 before. Didn't shoot the SBR at 600 but I have shot it out to 450 and I can hit with it. I need to get the 308 figured out to 600 so we definetly have to go out sometime and hit the 600.

I called Hornady to ask if they had data with an 11.5" barrel. They suggested using the 55 gr "ballistic tip" but if I wanted more penetration use the 75 gr. With the 11.5" barrel they reported with the 55 gr 68% fragmentation and 8.5" total penetration. With the 75 gr the fragmentation is 34% and total penetration 11.5".

Since the 75 gr has more mass a lower fragmentation % will provide more actual mass fragmenting than the % would suggest. I calculated the gr fragmented with the 55 gr at 37 gr and with the 75 gr, 26 gr.

I hope this data will help others in the same situation.

Although I may be (and probably am) wrong, it seems that standards developed from the 1986 Miami firefight:

As the article states, "In the real world you'd have to try pretty hard to find 12 inches of uninterrupted muscle to shoot through." It seems that fat and the abdomen would be much less dense than muscle. Lung tissue would offer very little resistance.